1. Field of the Invention
The present invention relates to a measurement of bit errors, and particularly, to acquisition of a synchronization between reception data past a DUT (Device Under Test) and expectation data by detecting synchronism patterns contained in the reception data and the expectation data.
2. Description of the Related Art
In cases of data communications by optical fibers there occurs a case causing a bit error. It is then necessary to detect the bit error to be corrected. FIG. 8 shows a system arrangement for making a detection of bit error.
A first pattern generator 52 gives electric data to a DUT (device under test as an element to be measured) 60. The DUT 60 has an E/O (electric/optic) converter 61, O/E (optic/electric) converter 62, and an optical fiber 63. The electric data given to the DUT 60 is converted by the E/O converter 61 into light, which is transmitted through the optical fiber 63 and returned by the O/E converter 62 again into electric data. The data output from the DUT 60 is called reception data.
A second pattern generator 54 generates expectation data for collation with the reception data. At a collator 56, the reception data is collated with the expectation data to find part of the reception data inconsistent with the expectation data, if any, as an inconsistent part to be a bit error.
At the collator 56, for collation between the reception data and the expectation data, there is needed a synchronism to be obtained between the reception data and the expectation data. There is thus detected a synchronism pattern contained in the reception data, and the expectation data is generated in accordance with the detected timing, thereby obtaining a synchronism.